This weapon is also from my home campaign. It took a little bit of tweaking but I like how the sweeps and knuckle guard shaped up to be a heart, complete with an angled crossguard that looks like a piercing arrow.
---
A cracked pink diamond glimmers at the rose pommel of this silver rapier. From the rose sprouts a rose gold guard and grip, twisting into soft silver roots that crawl up the blade. This rapier once belonged to a magnificent hero bard known to cause unmendable sorrow wherever they went. Contrary to expectations, its name did not describe the bard’s romantic interactions, but rather their propensity to produce widows.
---
Heartbreaker
Weapon (rapier), rare (requires attunement)
When you hit a creature with a melee weapon attack with this magic weapon, you deal an extra 1d8 psychic damage.
Sorrow Core. If you score a critical hit with this weapon, the creature bleeds for 1 minute, provided it is not undead or a construct. At the start of its turns, a bleeding creature must make a DC 15 Constitution saving throw, losing 1d4 hit points on a failed save and ending the bleeding condition on a success.